Posted
by
ScuttleMonkey
on Friday October 23, 2009 @03:43PM
from the scott-me-up-beamie dept.

carstene writes "The NASA Centennial Challenge Powered Beaming competition, to develop technology for uses such as a space elevator, or to power a rover in a shadowed crater on the moon, was delayed indefinitely due to trouble setting up the kilometer-high race track. It has now had the kinks worked out and is rescheduled for the week of November 2nd. The competition involves using a high-power laser to beam power to a robot that climbs a kilometer-high cable attached to a helicopter. The competition was previously covered on Slashdot."

1 m^3 of helium has about 1kg of buoyancy, to lift 1km cable along with the elevator would require a very large balloon, the winds at 1KM are much stronger then on the surface so the giant balloon would be blown all over the place with a laser pointed at it I'm sure you can figure out the rest.

"a few extra tonnes"? First off, space elevators aren't exactly high payload devices; the margins in most designs are generally tiny compared to the elevator's mass. But the big problem with what you wrote is that geosynchronous orbit is 26,199 miles up; a space elevator must be *at least* that long. You're looking at something like one ton per 10,000 miles, or one pound per five miles, or 17 milligrams of conductor per foot. Do you really think that's going to power anything? Even if you only provide power for part of the way up, it's still just not going to happen.

I think his point was that you could make a pretty straight 1 km bar along the ground. I thought the main thing being tested here is the ability to hit the target as it goes along the cable/bar to a distance of a km. Mimicing the resistance of gravity while moving in the horizontal plane is quite simple.

At some point though you do want a full system integration test, so perhaps that's what they are actually doing here.

I would wonder how 'stationary' the helicopter can actually be. I'd figure it would move around quite a bit given wind gusts at altitude; how much would an actual elevator ribbon move in the wind in practice?